[Samba] winbind looses connection to DC in 3.0.30

[Jens Nissen]

I have successfully joined a domain with Samba 3.0.30
But after approx. one or two hours, winbind looses
connection to the domain controller and users are not allowed
to connect shares.
After a 'killall winbindd' and restarting of winbind, the users
can connect to the shares again.

How can I work around this bug?

Configuration looks like this:

[global]
         dos charset = ISO-8859-1
         unix charset = ISO-8859-1
         display charset = ISO-8859-1
         workgroup = DOMAIN
         realm = DOMAIN.TEST
         server string = myserver
         interfaces = ixp0
         security = ADS
         allow trusted domains = No
         password server = sbs2000.domain.test
         private dir = /var/lib/adsamba/private
         passdb backend = tdbsam
         guest account = samba
         log level = 6
         log file = /var/log/adsamba/smblog.ad
         max log size = 0
         name resolve order = wins bcast host
         socket options = TCP_NODELAY IPTOS_LOWDELAY SO_KEEPALIVE 
SO_RCVBUF=8192 SO_SNDBUF=8192
         load printers = No
         show add printer wizard = No
         preferred master = No
         local master = No
         domain master = No
         wins server = 192.168.1.4
         idmap uid = 1000-60000
         idmap gid = 1000-60000
         winbind enum users = Yes
         winbind enum groups = Yes
         winbind offline logon = Yes
         admin users = DOMAIN\\Administrator
         ea support = Yes